\documentclass{standalone}

\usepackage{tikz}
% \usetikzlibrary{backgrounds}
% \usetikzlibrary{decorations.pathreplacing}

\renewcommand{\familydefault}{\sfdefault}

\begin{document}
\begin{tikzpicture}
\tikzset{page/.style={draw,circle,thick,minimum size=1cm}}
\tikzset{link/.style={->,>=latex,thick}}

\node at (0,0)  [page] (1) {1};
\node at (4,1)  [page] (2) {2};
\node at (0,-2) [page] (3) {3};
\node at (5,-1) [page] (4) {4};
\node at (3,-3) [page] (5) {5};

\draw [link] (1) -- (2);
\draw [link] (1) -- (5);

\draw [link] (2) -- (3);
\draw [link] (2) -- (4);
\draw [link] (2) -- (5);

\draw [link] (3) -- (5);

\draw [link] (4) -- (1);
\draw [link] (4) to [bend left=15] (5);

\draw [link] (5) to [bend left=15] (4);

\end{tikzpicture}
\end{document}

